[R-SIG-Mac] ?if

[Byron Ellis]

Actually there is help for control structures, help("if") works just 
fine. The problem is ? is that R's parser treats ? as an operator with 
unary and binary forms when, in fact, its not really an operator. 
?if(TRUE) TRUE (any valid IF construct) will also give the help for 
'if'. This is true for all platforms and probably has something to do 
with the fact that while "if" is bound directly to a primitive ( 
"if"(runif(1) < 0.5,TRUE,FALSE) is equivalent to if(runif(1) < 0.5) 
TRUE else FALSE) , the if bareword gets special handling in the parser.

On Feb 12, 2005, at 4:33 PM, Rob J Goedman wrote:

> John,
>
> Just to make sure, which configuration are you using?
>
> Assuming the GUI (otherwise you would see a "+" instead of the ">" 
> prompt), which version of
> the R.app are you using? The creation date listed in Finder will do.
>
> I think you noticed 2 issues. Right now, there is no ? help for 
> control structures. You have to go
> to the language reference manual. Secondly, newer versions of R.app 
> (just the GUI part, as
> released by Simon on http://www.rosuda.org/R/nightly/ ) will tell you 
> if there is no help for
> the requested topic.
>
> Hope this helps,
> Rob
>
>
> On Feb 12, 2005, at 1:22 PM, Dr. John R. Vokey wrote:
>
>> ? followed by any of the condition statements (or help() containing 
>> the condition statement)  does nothing (i.e., the help window fails 
>> to open), but the line is parsed in that the prompt `>' is returned.  
>> Is this a parsing error in the help function, or (more likely) have I 
>> missed some deep R construct?
>> --
>> John
>>
>>
>> --
>> John R. Vokey, PhD
>> Professor
>> B.E.R.G. - Behaviour and Evolution Research Group
>> Micro-Cognition Laboratory
>> Department of Psychology & Neuroscience
>> University of Lethbridge
>> Lethbridge, Alberta T1K 3M4
>> CANADA
>>
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>
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---
Byron Ellis (ellis at stat.harvard.edu)
"Oook" -- The Librarian